JS/HTML Formatter

The JavaScript and HTML Formatter re-indents compressed or messy code so you can read it again. Paste a minified production script, a single-line HTML document, or a snippet a colleague sent without line breaks, choose an indent style, and the beautifier expands it into consistently indented, structured code. It is for developers inspecting third-party bundles, debugging output from a code generator, or standardizing indentation before adding a file to a project.

How to Use

1. Pick the mode — JavaScript or HTML — so the formatter applies the right grammar.
2. Paste the code into the input area. Output updates once you click Format or press Ctrl+Enter.
3. Choose an indent style: two spaces, four spaces, or tabs.
4. Copy or download the result. The panel also shows the original and formatted byte sizes, which is a useful reminder of how much of a minified file was whitespace.

What Beautifying Changes — and What It Does Not

Formatting touches whitespace and only whitespace. It adds newlines between statements, indents blocks according to their nesting, and aligns continuation lines. It does not rename variables, reorder statements, add or remove semicolons that carry meaning, or convert syntax. That restraint is what makes it safe: the formatted file and the original execute identically.

The practical value is diagnostic. When ten statements and four nested blocks sit on one line, a mismatched brace is invisible. Once each block is on its own indented line, the same brace stands out immediately. Reading minified vendor code to find the function you need to override is the other common use — beautifying turns a wall of characters into a navigable file.

A Worked Example

A minified snippet arrives looking like this:

function total(items){let sum=0;for(const it of items){if(it.active){sum+=it.price*it.qty;}}return sum;}

After beautifying with two-space indentation:

function total(items) {
  let sum = 0;
  for (const it of items) {
    if (it.active) {
      sum += it.price * it.qty;
    }
  }
  return sum;
}

Nothing about the computation changed. What changed is that the if is now visibly inside the loop, the accumulator is declared before it, and the return sits outside — the structure is legible at a glance instead of being reconstructed in your head.

HTML benefits in the same way. A template emitted by a framework often arrives as one line of nested tags, and re-indenting it reveals which elements wrap which. That is especially useful when auditing a page for accessibility: once the hierarchy is visible, a heading that jumps from h2 to h4 or a list whose items sit outside the list element stands out immediately. The formatter does not validate the markup, but it makes the nesting readable enough to review by eye.

Choosing an Indentation Style

• Two spaces — the de facto JavaScript default and what most linters assume. Compact, and it keeps deeply nested code from drifting far to the right.
• Four spaces — more pronounced nesting cues, common in Java-influenced codebases and some TypeScript projects.
• Tabs — one character per level; each reader sets their preferred display width, which is why some teams prefer them despite the mixing risks in shared code.

Whichever you choose, run the formatter before you start editing, not after. Reformatting a file you have already changed produces a diff full of whitespace noise, burying the real edits — a habit that costs reviewers time in every pull request.

Common Mistakes

• Expecting minification. The tool only expands; use a dedicated minifier in a build step when you need the opposite.
• Pasting HTML into JavaScript mode. Tags are not JavaScript statements; select the matching mode or the output will be wrong.
• Assuming formatting fixes syntax errors. If the code does not run before beautifying, it will not run after. A formatter reorganizes valid tokens; it does not repair invalid ones.
• Formatting inside a string literal. Text inside quotes is data, not code. A formatter leaves it alone, but be careful when hand-editing around templated HTML or SQL embedded in strings.
• Losing the original. Keep the minified source if you plan to diff against it later; the beautified version is for reading, not for shipping.

Features

• Beautify JavaScript and HTML with structured indentation
• Indent styles: two spaces, four spaces, or tabs
• Scope-aware formatting that respects blocks, loops, and nesting
• Original and formatted size display
• Copy to clipboard or download as a file
• 100% client-side — private code never leaves the browser

Use Cases

• Debugging minified code: Expand a production bundle to find where something breaks.
• Reviewing third-party libraries: Re-indent a dependency to understand what it does.
• Code cleanup: Normalize indentation when merging snippets from different sources.
• Learning: Format generated HTML to see how a document is actually nested.
• Bug reports: Produce readable code before pasting it into an issue or a review.

Related Tools

• CSS Minifier/Formatter
• JSON Formatter
• HTML Encoder/Decoder
• XML Formatter